I have accused them of being bad writers for a vast number of reasons over the years
We are not talking about that. We're talking about the post you made where you claimed it was bad writing to cast a U.S. politician to endorse the idea that fighting racist voter suppression laws is a good thing via subtext.
But this one thing is one of the results of that writing. Nuance replaced by what was essentially a picture of someone flashing on screen.
Pure nonsense. There was a clear subtext to Abrams's appearance to anyone who is familiar with U.S. politics. You were not, and therefore you did not pick up on the subtext. You missed a piece of nuance. The fact you didn't understand the subtext of the scene does not make it bad writing.
It was absolutely subtext, because the framing of Abrams (and the subsequent publicity about her cameo) makes it clear that the producers intended for the audience to understand that they were endorsing her politics if the audience recognized her, yet this was done without spelling it out explicitly. This is literally Subtext 101.
and has nothing got to do with the examples you gave. Immigrant Song is about people who "come from the land of the ice and snow" and were about to be immigrants
And here we have another example of you not understanding subtext. "Immigrant Song" is about Viking colonialism.
Thor: Ragnarok is about Asgardian colonialism coming home to roost in the form of their old tool of colonial oppression, Hela, returning to destroy the Asgardian state and murder its people; like many wealthy imperialist nations in real life, Asgard has ignored or forgotten its violent past -- Hela exposes how her campaign of violence and conquest was literally covered up by Odin, and now she is treating Asgard as Asgard once used her to treat its colonial subjects. The film ends with the Asgardians becoming refugees just as colonialism itself often creates refugees.
There is an clear irony in Led Zepplin as creators choosing to juxtapose a song that is textually about colonizers with the title "Immigrant Song," and there is a further irony in juxtaposing a depiction of former colonizers becoming refugees with said song. The subtext is very clear: Colonial violence will eventually come home to roost for the colonizers. Heroism lies in, like Thor, learning to accept the past as it truly was and take responsibility for dismantling colonialist power structures (symbolized by him literally unleashing Ragnarok and destroying the Asgardian planetoid).
What was the connection between Abrams and what was happening in Discovery?
As I, and others, have already said, the clear subtext was that Paradise expects those viewers who recognize Abrams to understand that by featuring Abrams,
Star Trek: Discovery as a narrative is endorsing the political project for which she has become most well-known (leading the opposition to Georgia's racist voter suppression laws). The subtext, therefore, is an endorsement of the idea of multi-racial democracy and of progressive politics more broadly. It relates to the events of
Star Trek: Discovery by implying that progressive politics is the real-world embodiment of the themes the show had just espoused -- diplomacy over violence, diversity over homogeneity, democracy over autocracy, peace over war. The episode is designed to work fine if you
don't recognize her, but recognizing her adds a layer of meaning to the text.